Round Valley Regional Preserve is one of the East Bay Regional Park District's lesser-known jewels. Located on Marsh Creek Road in east Contra Costa County, Round Valley has expanses of level grassland and rolling hills of oak woodland that can be accessed on several hiking trails of varying difficulty.
One moderate year-round hike is a 4.8-mile loop from the parking lot. Cross the large concrete bridge and turn left onto Hardy Canyon Trail. Stroll along Marsh Creek for about a quarter mile, and then turn south as you pass an old adobe building, a remnant of the park's farming days.
Hardy Canyon is a long but gradual climb along seasonal High Creek. After a storm, the creek showcases many small waterfalls and cascades. A saddle summit at about 1,000 feet surprises the hiker with sweeping vistas of Round Valley and the eastern slopes of Mount Diablo. As you enjoy the view, take note that one of the long valleys to the west was proposed as a landfill site in the 1980s. Thankfully, that idea was voted down and the preserve now forms part of an arc of more than 50,000 acres of protected open space stretching from Walnut Creek to Livermore.
The descent to Round Valley passes rock outcroppings, a few switchbacks, and more oak woodland. Turn east on the Miwok Trail for another stroll along Round Valley Creek back to the parking lot.
Hike by John Gallagher, originally published in the January 2010 issue of Bay Nature magazine